I. Acute Leukaemias
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A. Lymphoblastic:
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-Accounts for 20% of all acute leukaemias.
-Accounts for 80% of childhood leukaemia.
-Peak incidence at age 4 years.
Most patients present with an acute illness of several days or less frequently, with tiredness or non-specific aches over several weeks or months.
-Clinical features can be grouped into:
1. Consequences of bone marrow failure - anaemia, bleeding, vulnerability to infection.
2. Consequences of accumulation of leukaemic cells.
Important Points to remember:
-The patient with acute lymphoblastic leukaemia is usually a child, whereas the patient with acute myeloid leukaemia is rarely a child.
-Although the marrow is usually extensively replaced by leukaemic cells, elated symptoms are uncommon. Rarely there may be bone tenderness in childhood ALL.
-A common presentation of childhood ALL is with joint and muscle pain. ALL does not infiltrate extra-medullary tissues - lymph nodes, spleen, liver, meninges - as much as AML.
-T cell ALL may present with superior vena caval obstruction.
B. Myeloid:
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-Accounts for 80% of acute leukaemias
-Peak incidence between 15 and 39 years
It is important to distinguish between AML and ALL:
-Morphological - Auer rods pathognomic of AML
-Histo-chemical stains for myeloid enzymes such as peroxidase or chloroacetate confirm AML
surface markers characteristic of primitive lymphoid cells identify ALL, e.g. terminal deoxynucleotide transferase present in 95% of cases of ALL
-Primitive B lymphocyte antigens such as CALLA, B1, BA1 may help to identify ALL
-T cell ALL diagnosed by rosette formation with sheep erythrocytes or identification of cell markers by monoclonal antibodies such as Leu-1 or Leu-9
II. Chronic Leukaemias
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CLL usually has an insidious onset. Approximately 25% of patients are diagnosed incidentally when they are found to have lymphocytosis. Rapidly progressive CLL occurs occasionally and is characterised by larger, less mature - appearing lymphocytes - "prolymphocytic" leukaemia.
Typical clinical features of CLL include:
-Non-specific symptoms - lethargy, weight loss, fever and sweating, and infections.
-Attributable to anaemia and thrombocytopenia - which may be autoimmune.
-Lymphadenopathy - occurs in 80% of cases. Typically, moderate enlargement, affecting nodes in the neck, axilla and groin. Classically, symmetrical with non-tender, rubbery nodes. May have developed over a period of months or years.
-Hepatosplenomegaly - in 50% of cases.
-Skin lesions - pruritus, Herpes zoster, generalised infiltration (l'homme rouge, usually associated with pruritus), vesibullous lesions
The clinical features of chronic myeloid leukaemia may be classified into:
non-specific systemic features:
-anaemia
-malaise & fatigue
-weight loss
-sweating
common features:
-bleeding diathesis
-discrete ecchymoses
-menorrhagia
-splenomegaly
-hepatomegaly
rare features:
-abdominal pain or pleuritic pain due to splenic infarction
-gout
-retinal haemorrhages
-priapism
-fever
comparison of CML and CLL
-lymphadenopathy
CML: uncommon
CLL: common
-hypogammaglobulinaemia
CML: not feature
CLL: may occur
-positive Coomb's test
CML: not feature
CLL: may occur
-development of blast
CML: common
CLL: not common crisis
-prognosis
CML worse than CLL
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